Spring



The design is for a spring which is intended to be used in association with sporting equipment.

FIG. 1 is a plan view showing the appearance of the convex and concave surfaces of my new design for a spring, except for the surface curvature that is illustrated in FIG. 2; and,

FIG. 2 is a side view of the spring. 

The ornamental design for a spring, as shown and described. 